High winds, unique clouds break dry, hot streak

July 31, 2015

A lull in the dry, hot conditions brought some change this week to the recently uneventful weather in Bowman County.

The National Weather Service in Bismarck issued numerous severe thunderstorm warnings for Bowman County on Monday evening, as a strong system moved into westernNorth Dakota from Montana.

Pea-sized hail, heavy rain and frequent lightning were the bulk of the weather events across the county from that storm.

Once the storm passed, however, a unique yet eerie formation of clouds attracted vast social media attention from area residents. A long stretch of rolling, ball-shaped clouds made for a perfect summertime photo, draped in front of the colorful sunset. People took notice and started posting such photos to Facebook.

The clouds were identified as mammatus clouds, a pouch-like cloud structure. According toAccuWeather.com, they’re a rare example of clouds in sinking air—most clouds form in rising air.

For a mammatus cloud to form, according to the website, the sinking air must be cooler than the air around it and have high liquid water or ice content. They derive their name from their appearance, like the bag-like sacs that hang beneath the cloud resemble cow’s udders.

Mammatus clouds are long-lived if the sinking air contains large rain drops and snow crystals since larger particles require greater amounts of energy for evaporation to occur. Over time, the cloud droplets do eventually evaporate and the mammatus clouds dissolve.

They are in essence upside-down clouds. The sharp boundary of mammatus is much like the sharp boundary of a rising cumulonimbus cloud before an anvil has formed.

Despite popular misconception, mammatus clouds are not a sign that a tornado is about to form.

While associated with thunderstorms, mammatus clouds are not necessarily an indicator of severe weather.

The clouds stretched for miles across the area before dusk on Monday.

The sign hanging above Twin Butte Liquor in Bowman was destroyed Tuesday after the area experienced high sustained winds and gusts over 50 mph. (Courtesy photo)

As the short-lived severe storm system moved northeast out of the county, the National Weather Service issued a high wind warning for most of western North Dakota, including Bowman and Slope Counties. It went into effect from the early Tuesday morning hours to Tuesday evening.

The forecast called for strong, sustained winds, with gusts potentially topping 70 mph.

Bowman County’s highest wind gust was recorded at 52 mph, which occurred around 2 p.m. Tuesday.